Copper -bipyridyl complex

The orange complex 83 (57) exhibits a pseudotetrahedral geometry in the solid state, with the chlorine atoms distorted 49° and 63° away from the bipyridyl-Cu plane (Fig. 8). The d-d transition occurs at 919 nm. It seems likely that the large size of the ligand substituent is responsible for the deviation in the structure of the copper complex. Whether this effect is also responsible for the ease of reduction of the corresponding triflate complex by diazoester is not clear. 

High-spin/low-spin transitions bipyridyl metal complexes, 90 iron complexes, 94 polypyridyl metal complexes, 91 Histamine metal complexes, 82 Histidine copper complexes naturally occurring, 965 metal complexes, 746 naturally occurring, 966 reactivity, 756 stereoselectivity, 754 Schiff bases... 

The oxidation of primary aliphatic alcohols by l w(2,2,-bipyridyl)copper(ll) permanganate (BBCP) in aqueous acetic acid leads to the formation of the corresponding aldehydes446. The oxidation of [l,l-2H2]ethanol exhibited446 a kn/kn of 4.50. The formation constants for BBCP-alcohol complexes and the rates of their decomposition have been evaluated. Aliphatic aldehydes are oxidized by pyridinium hydrobromide... 

The synthesis of the optically active chroman 489 can be achieved by use of a catalytic asymmetric tandem oxa-Michael addition Friedel-Crafts alkylation sequence between 3-methoxyphenol and (/. (-methyl 2-oxo-4-phenylbut-3-enoate. The chiral C2-symmetric box managanese(n)- complex 490 exerts excellent stereocontrol upon the reaction (Equation 200) <20030BC1953>, whereas only moderate enantioselectivity is observed in the presence of a chiral C2-symmetric 2,2 -bipyridyl copper(n)- complex (42% = ee) <20050L901>. 

Recently, the cis-distorted octahedral complex [Cu(bipy)2(ONO)]NOs has been discussed and compared with the copper complexes listed in Table I (590a, 590h). The bipyridyl ligand in Irl2(OOC CHs)(CO)(bipy) has been found to be nonplanar (4a). 

Phenanthroline and 2,2 -bipyridyl form complexes, although not intensely coloured, with Ru, Os, and Cu(I). Many metals e.g., Zn and Cd) can form colourless complexes with phenanthroline and bipyridyl, which are more stable than the corresponding Fe(II) complexes. When determining Fe in the presence of Zn or Cd, EDTA should be used as a masking agent [31]. Copper can be masked with triethylenetetramine [32]. 

Iron-phthalocyanine (Fe-Pc) encapsulated in Y and VPI-5 zeolites were used for the oxidation of alkanes or olefins in presence of t-butylhydroperoxide or H2O2 (Fig. 9). Fe-Pc-Y also catalyzed the oxidation of cyclohexane to cyclohexanol and cyclohexanone with t-butylhydroperoxide ( TBHP ). Ruthenium perfluorophthalocyanine complexes encapsulated in NaX ( Ru-Fi6 Pc-X ) were active for the oxidation of cyclohexane with TBHP at room temperature.Manganese(II) bipyridyl complexes in faujasite ( Y ) zeolite are active for the oxidation of cyclohexene to adipic acid in the presence of H2O2 at room temperature. Similarly oxidation reactions have been reported using copper complexes encapsulated in X,Y, and VPI-5 molecular sieves. 

Fig. 10. Structure of terpyridyl (6), bipyridyl (7), and neocuproine (8) copper complexes.

Furthermore, the presence of bipyridyl increased the selectivity of the copper catalyzed oxidation to peracetic acid. For example, oxidation of propionaldehyde in acetic acid at 30 °C in the presence of [Cu(bipy)2(N03)2] gave the peracid in 58% yield and the acid in yields of 32-40%. When reaction was run using Cu(N03)2 in the absence of bipyridyl, the peracid was formed in 9% yield while the yield of carboxylic acid was 80%. The nature of the amine was varied and the catalytic activity of the copper complex toward oxidation of propionaldehyde varied with the amine as follows bipyridyl, phenanthroline > none, pyridine > 2,9-dimethyl-l, 10-phenan-throline > quinoline > ethylenediamine. The rate equations for oxidation in the presence of Cu(N03)2 and [Cu(bipy)2(N03)2] differed substantially and the apparent activation energies were 8.2 and lO.lkcal/mole, respectively [241]. 

The bipyridyl groups could be used as coordination sites, while pyridyl sites could be protonated to incorporate specific negatively charged chelating ligands. These films were used to analyze for iron and copper complexes in solution. 

Enantioselective Friedel-Crafts alkylation reactions were performed between substituted indoles and methyl trifluoropyruvate, using a chiral nonracemic ( -symmetric 2,2 -bipyridyl copper triflate complex as catalyst. The active copper(II) catalyst was... 

Haines RJ, Wittrig RE, Kubiak CP (1994) Electrocatalytic reduction of carbon dioxide by the binuclear copper complex [Cu2(6-(diphenylphosphino-2,2 -bipyridyl)2(MeCN)2][PF6]2. Inorg Chem 33 4723 728... 

The most common catalysts for ATRP are complexes based on a copper(T) halide and nitrogen based ligand(s). Various ligands have been employed and those most frequently encountered are summarized in Table 9.5. Typically, four nitrogens coordinate to copper. The bidentate bipyridyl (bpy) ligands 132-133 are known to form a 2 1 complex. The tetradentate ligands are expected to form a 1 1 complex. 

Rate and equilibrium constant data, including substituent and isotope effects, for the reaction of [Pt(bpy)2]2+ with hydroxide, are all consistent with, and interpreted in terms of, reversible addition of the hydroxide to the coordinated 2,2 -bipyridyl (397). Equilibrium constants for addition of hydroxide to a series of platinum(II)-diimine cations [Pt(diimine)2]2+, the diimines being 2,2 -bipyridyl, 2,2 -bipyrazine, 3,3 -bipyridazine, and 2,2 -bipyrimidine, suggest that hydroxide adds at the 6 position of the coordinated ligand (398). Support for this covalent hydration mechanism for hydroxide attack at coordinated diimines comes from crystal structure determinations of binuclear mixed valence copper(I)/copper(II) complexes of 2-hydroxylated 1,10-phenanthroline and 2,2 -bipyridyl (399). 

This work has been developed further through the use of a copper(I) bipyridyl complex catalyst, incorporating a chiral and sterically demanding ligand, and... 

Copper(I) chloride forms complexes with ethylene and other alkenes in solutions that may have compositions such as [Cu(C2H4)(H20)2]" or [Cu(C2H4)(bipy)]+. (bipy = bipyridyl)... 

Other workers have employed different sensitiser systems, e.g. duel sensitisation by a zinc porphyrin and copper phthalocyanine on TiOj, Eosin Y or tetrabro-mophenol blue on ZnO, and a ZnO/SnOj mixture with a ruthenium bipyridyl complex, to produce good energy conversion factors. 

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